Effects of Vitamin E on the Osteoblast Differentiation

Abstract

ABSTRACT. Vitamin E is thought to affect bone formation and bone remodeling. In this study, we investigated the effects of vitamin E (-tocopherol and -tocopherol) on the osteoblasts isolated from rat calvariae. At 4 and 7 days (Day 4 and 7) after induction of osteoblastic differentiation, treatment of -tocopherol (100 and 200 M) and -tocopherol (2 and 20 M) for 3 days significantly decreased alkaline phophatase activity of the cultured osteoblasts. At Day 14, however, no significant change was detected in ALP activity and expression of bone sialoprotein mRNA in the osteoblasts treated with -tocopherol or -tocopherol for 3 days. Expression of osteocalcin mRNA was decreased by treatment of -tocopherol (100 and 200 M) and -tocopherol (2 and 20 M) at Day 4 and 7. At Day 14, expression of osteocalcin mRNA was decreased only with treatment of 200 M -tocopherol. In addition, the noncalcified nodules were decreased by treatment of -tocopherol (200 M) and -tocopherol (20 M) at Day 7. However, treatment of -tocopherol and -tocopherol showed no significant change of formation of calcified nodules at Day 14. These results indicate that vitamin E inhibits differentiation of osteoblasts especially from early stage to osteoid-producing stage.KEY WORDS: alkaline phosphatase, cell culture, osteoblast, osteocalcin, tocopherol.J. Vet. Med. Sci. 72 (7): [951][952][953][954][955][956][957] 2010 Vitamin E (tocopherols and toctrienols) is an important cellular antioxidant that participates in several reactions to prevent peroxidation of membrane-bound lipids. Recently, many non-antioxidant functions of -tocopherol, a major vitamin E isoform, were described at cellular level, such as inhibition of proteinkinase C, inhibition of the smooth muscle cell proliferation and the activation of diacylglycerol kinase [3,4,[7][8][9]. In the skeletal system, several reports demonstrated effects of vitamin E on bone and cartilage tissues [1,20,28,32]. Ebina et al. reported that Fe-induced impairment of bone formation was prevented by dietary vitamin E supplementation in rats [13]. In addition, vitamin E stimulated trabecular bone formation in chicks [25]. Therefore, vitamin E is thought to affect bone formation and bone remodeling. However, direct effects of vitamin E on bone tissue at cellular level are still remained unclear. Among tocopherol isoforms, -tocopherol shows the most biologically active and is selectively retained in the body [2,15], and -tocopherol exhibits the most inhibitory effect to cell proliferation in several cell-types [23,24]. In this study, to test the influence of vitamin E on differentiation of osteoblasts at several stages of osteogenesis, we investigated change of alkaline phosphatase activity (ALP), and expression of osteocalcin and bone sialoprotein (BSP) as a marker of maturation of osteoblasts [17,27,31] in cultured osteoblasts by treatment with  and -tocopherol.Osteoblasts were isolated from calvariae of newborn rats by collagenase digestion according to the method described by Spector e...

Effects of vitamin E on bone turnover markers among US postmenopausal women

“…(77,79) A recent in vitro study showed that alpha-tocopherol inhibited differentiation of osteoblasts. (80) Given that BAP reflects the differentiation stage of osteoblastogenesis, (81) it is possible that excess alphatocopherol intake may reduce BAP levels. Although we found significant inverse associations between total alpha-tocopherol intake and serum alpha-tocopherol and BAP levels in the unadjusted analysis, these relationships disappeared after adjusting for confounders.…”

Effects of vitamin E on bone remodeling in perimenopausal women: Mini review

“…Soeta et al [5] suggested alpha-and delta-tocopherol inhibited the differentiation of osteoblasts, especially from early stage to osteoid-producing stage in cultures of osteoblasts isolated from rat calvariae. An interesting finding on the dose-dependent paradoxical effect of gamma-tocopherol on osteoblasts cell culture was described by Abd Manan et al [6]: low doses (1 and 10 M) protected osteoblasts against H2O2-induced oxidative stress and apoptosis; however, high doses (100 M) reduced glutathione peroxidase activity and promoted apoptosis.…”

Deneysel periodontitis oluşturulmuş diyabetik sıçanlarda α-tokoferol’ün alveoler kemik kaybı üzerine etkileri

“…Soeta ve ark. 46 tarafından yapılan çalışmada δ-tokoferol ve α-tokoferol'ün osteoblast farklılaşması üzerinde etkili olduğu bildirilmiştir. İlk yedi günlük dönemde α-tokoferol ve δ-tokoferol uygulamasıyla alkalen fosfataz aktivitesinin ve kalsifiye olmamış nodül sayısının azaldığı rapor edilmiştir.…”

“…Vitamin E uygulamasının osteoblast farklılaşmasını osteoid üretiminin erken fazında etkilediği belirtilmiştir. 46 Periodontal doku yıkımında tedaviye yardımcı olarak E vitamini uygulanmasına yönelik çalışmalar sınırlı sayıdadır. 21,47 Sıçanlara diyetle birlikte verilen E vitaminin üç ay sonunda AKK üzerine etkili olmadığı, ancak rotasyonel strese bağlı oluşan kemik yıkımına yatkın bölgelerde E vitamini uygulamasının koruyucu bir etki sağlayabileceği belirtilmiştir.…”